In order to provide wideband mobile communication services which cannot be provided by the second generation mobile communication systems due to technical limitations, the International Telecommunication Union Telecommunication Standardization Bureau (ITU-T) provides the third generation mobile communication systems. The Wideband Code Division Multiple Access (WCDMA), which is one of the main candidate schemes of the third generation mobile communication, gets extensive application due to its good compatibility with the GSM system based on the Global System for Mobile Communications Mobile Network Application Part (GSM MAP) core network by using Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (UTRAN) as a wireless interface.
In the WCDMA, the cell update technology is an important process in WCDMA access technologies. When change of a location, a wireless link failure, etc., occur in a User Equipment (UE) in a connected state, this process is required to be used to inform the network to achieve UTRAN registration area update, or obtain new radio resources. Several main reasons why the UE initiates cell update will be described below.)
1) When a UE in a UTRAN Registration Area_paging Channel (URA_PCH or Cell_Paging Channel (Cell_PCH) state reenters a service area, the network needs to be informed to initiate a URA update or a cell update process.
2) When there is an unrepairable RLC error on an Acknowledge Mode-Radio Link Control (AM RLC) entity, the network needs to be informed to initiate cell update.
3) A UE in a Cell_forward Access Channel (Cell_FACH), Cell_PCH, URA_PCH state periodically initiates a cell update or URA update process.
4) When cell update is required to be implemented after cell reselection, the UE is in other connected states other than a Cell_Dedicated transmission channel (Cell_DCH) state.
5) When a wireless link failure or transmission UE capability information failure occurs in the UE in the Cell_DCH, cell update is initiated.
6) Since a paging of the network or uplink transmission data that requests transfer from the Cell_PCH state, the URA_PCH state to the Cell_FACH state is received, cell update is required to be initiated.
7) When the UE in a connected state other than the Cell_DCH state receives Multimedia Broadcast Multicast Services (MBMS), cell update is required to be initiated.
It can be seen from the above description that the cell update procedure is widely used in a Radio Network Controller (RNC) and NodeBs which is under the jurisdiction of the RNC, and is also used between RNCs with an Iur interface. The cell update procedure is mainly implemented based on a signaling process in the Iur interface Radio Network Subsystem Application Part (RNSAP) protocol, and specifically, based on an uplink signaling transfer indication. In the implementation process, a wireless link establishing process or a public transmission channel resource initialization process in the RNSAP protocol may also be initiated for a target RNC according to actual conditions, and a wireless link deletion process or a public transport signal resource release process in the RNSAP protocol is initiated for a source RNC.
The process of cell update between he RNCs is that: after a UE in a connected state, such as Cell_DCH state, or Cell_FACH state, or Cell_PCH state, or URA_PCH state, is resided in a cell which is under the jurisdiction of another RNC (which is referred to as a Drift RNC (DRNC), or a Target RNC (TRNC)) for the above reasons, the UE sends a cell update message to the DRNC; after receiving the message, the DRNC sends an uplink signaling transfer indication to a Source RNC (SRNC) through the :fur interface between the RNCs; the SRNC initiates a Service Radio Network Subsystem Relocation (SRNS Relocation) process; the DRNC sends a cell update confirmation message to the UE after the relocation process ends; and a subsequent signaling process proceeds as needed after the cell update process ends.
In the modern wireless network system construct on, indoor coverage has become the most important part of the network construction, On one hand, a suitable indoor coverage scheme can allow the network to play its role furthest, and create greater value for operators; on the other hand, the suitable indoor coverage scheme can also greatly save the cost of network construction for the operators, and authentically achieve low-input high return. As a result, a radio access device called home NodeB emerges as the times require. Home NodeBs as exclusive resources of private users are deployed in private places such as homes, groups, companies or schools, so as to provide various high-speed radio access services and tariff concessions to the users, while makes up for a contradiction of insufficient coverage of existing distributed cellular wireless communication systems.
FIG. 1 is a schematic diagram of a network layout of a WCDMA system. As shown in FIG. 1, Home NodeBs are introduced in the WCDMA system. The home NodeBs are connected to a core network through a home NodeB gateway, and interfaces between the home NodeBs and the home NodeB gateway are hills. The home NodeB gateway provides services, such as registration, for the home NodeBs, and is similar to a RNC such that the existing core network can communicate with the home NodeB gateway using the existing Iu interface. However, there is no interface between the home NodeB gateways, so they cannot communicate directly.
With widespread deployment of the home NodeBs and great increase of users, after a UE originally located in a home NodeB and being in a connected state initiates cell update for some reason, if a target cell is not a source home NodeB cell, the cell update can not be implemented, the network will actively release the UE, and the UE will return to an idle state, which will seriously affect user experiences. Likewise, after the UE originally located in a macro cell and being in a connected state initiates cell update, if the target cell is a home NodeB cell, the problem of releasing will also occur.
Therefore, how to deal with the cell update procedure between the home NodeB gateways or between the home NodeB gateway and the RNC becomes a problem required to be solved.